Gravitational Field

Question 1

Define Newton’s Law of Gravitation

Answer 1

Two point masses attract each other with a force that is directly proportional to the product of their masses and inversely proportional to the square of the distance between them.

Question 2

Define Gravitational Field

Answer 2

Region of space in which a mass experiences a force due to the presence of another mass.

Question 3

Define Gravitational Field Strength

Answer 3

Gravitational force per unit mass acting on a test mass placed at that point.

Question 4

Define Gravitational Potential Energy

Answer 4

Work done by an external agent in bringing the mass from infinity to that point.

Question 5

Define Gravitational Potential Φ

Answer 5

Work done per unit mass by an external agent in bringing a test mass from infinity to that point.

Question 6

Explain why gravitational potential is always negative

Answer 6

Due to the attractive nature of gravitational force/field, the external force needed to bring a unit mass from infinity to a point without a change in KE must act in a direction opposite to the displacement vectors.

Question 7

Explain why the apparent weight/g at the equator is less than that at the poles

Answer 7

When an object is at the equator, part of the gravitational force acting on the it is used to provide the required centripetal force to do circular motion around the earth.